In access class barring (ACB), user equipment (UE) may be assigned to one of ten access classes (AC) 0-9, or may be assigned to one of five special categories: access classes 11-15. The access class of a user equipment may be stored in a subscriber identity module (SIM) or in a universal subscriber identity module (USIM). When a radio access network is overloaded, it may implement access class barring to select one or more access classes to block from registering, or to block from assigning to bearer resources of the radio access network.